USB Controllers

There are three types of USB host controllers:

  • Open Host Controller Interface (OHCI)

  • Universal Host Controller Interface (UHCI)

  • Enhanced Host Controller Interface (EHCI)

OHCI and UHCI controllers are both USB 1.1 controllers, which are capable of a maximum of 12 Mbps. EHCI controllers are USB 2.0 controllers, which are capable of a theoretical maximum of 480 Mbps. To get greater than USB 1.1 speeds, you must have a USB 2.0 controller, as well as USB 2.0 devices, hubs, and cables. A USB 2.0 device attached to a USB 1.1 hub will only be able to run at USB 1.1 speeds.

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